#include <stdio.h>

#define HEX_SIZE 9
#define OCT_SIZE 12
#define SIZE 12
#define DATA_SIZE 3

char display[SIZE + 1];
int data[DATA_SIZE]; // 16 bit use only 12
int i, j, k;

void clear_display() {
    for (i = 0; i < SIZE; display[i++] = '0');
}

void plus() {
    for (i = 2; i > -1 && (i == 2 || !data[i + 1]); i--)
        data[i] = (data[i] + 1) & 0xFFF;
}

void minus() {
    for (i = 2; i > -1 && (i == 2 || data[i + 1] == 0xFFF); i--)
        data[i] = (data[i] - 1) & 0xFFF;
}

void cast_to_oct() {
    for (i = 0, j = 0; i < OCT_SIZE; i++, j = i / 4, k = (3 - (i % 4)) * 3)
        display[i] = ((data[j] & (0x7 << k)) >> k) + '0';
}

void cast_to_hex() {
    for (i = 0, j = 0; i < HEX_SIZE; j = ++i / 3, k = (2 - (i % 3)) * 4)
        display[i + 3] += (display[i + 3] = ((data[j] & (0xF << k)) >> k)) > 9 ? 'A' - 10 : '0';
}

int main() {
    data[2] = 2045;
    clear_display();

    // print binary
    for (i = 0; i < 3; i++)
        for (j = 11; j > -1; j--)
            printf("%d", (data[i] & (1 << j)) >> j);
    printf("\n");
    // print binary

    cast_to_hex();
    printf("HEX:%s\n", display);
    cast_to_oct();
    printf("OCT:%s\n", display);
    return 0;
}